This is a repost from a question asked on the (now disfunct) bigquery forum.
While uploading data from the bq tool I get the following error:
BigQuery error in load operation: Unexpected. Please try again.
I’ve tried running several files, but each gives the same exception.
The latest failed job is job_5251c0bf5eb24436a350bdfbdbdb3cd8
It looks like that job hit a SECURITY_VIOLATION error. This is likely due to a line that is longer than the maximum line length (64k).
In the next build of BigQuery (which will probably go live next week) it will give you a better error in this case — it will tell you which lines are too long, and long lines won’t cause the import to fail (subject to the maxBadRecords limit).
In the meantime, you can make sure that your input lines are shorter than 64k (note that newlines can be quoted, so stray quotes can cause lines to appear to be too long).